Alkyllead antiknock fluids

ABSTRACT

INCORPORATION OF SMALL AMOUNTS OF METHYL BROMIDE OR ETHYL BROMIDE, OR BOTH, INTO TETRAETHYLLEAD-CONTAINING ANTIKNOCK FLUIDS HAVING A SCAVENGER COMBINATION OF ETHYLENE DIBROMIDE AND ETHYLENE DICHLORIDE WHEREIN THE LATTER SCAVENGER PREDOMINATES. THE FLASH POINT BY TAG CLOSED CUP (ASTM DESIGNATION: D 56-64) IS RAISED TO ABOVE 100*F.

United States Patent 3,578,606 ALKYLLEAD ANTIKNOCK FLUIDS Martin B. Smith and Norman G. Adams, Baton Rouge, La., assignors to Ethyl Corporation, New York, N.Y. No Drawing. Filed May 27, 1968, Ser. No. 732,094 Int. Cl. (109k 3/00; C101 1/20 US. Cl. 252-386 14 Claims ABSTRACT OF THE DISCLOSURE Incorporation of small amounts of methyl bromide or ethyl bromide, or both, into tetraethyllead-containing antiknock fluids having a scavenger combination of ethylene dibromide and ethylene dichloride wherein the latter scavenger predominates. The flash point by Tag closed cup (ASTM designation: D 56-64) is raised to above 100 F.

This invention relates to alkyllead antiknock fluid compositions of enhanced non-flammability characteristics. More particularly, this invention relates to the incorporation into certain alkyllead antiknock fluid compositions of very small quantities of one or a combination of additives to increase the closed cup flash point of the resultant composition to above 100 F.

As is well known in the art, the flammability of various organic liquids, especially for interstate shipping purposes, is ascertained with reference to certain standard test procedures, notably flash point tests. In accordance with these procedures, the higher the flash point, the less flammable is the liquid.

Alkyllead antiknock fluid compositions have long been considered entirely safe from the flammability standpoint because of the fact that they generally have high flash points pursuant to the standard Tag open cup flash point procedure (ASTM designation: D 1310-67). For example, commercial antiknock fluids composed of tetraethyllead, about one-half theory of ethylene dibromide and about one theory of ethylene dichloride have an open cup flash point of about 245 'F.

However, more recent events have indicated the desirability of insuring that the flash point of alkyllead antiknock fluids as measured by the Tag closed tester (ASTM designation: D 56-64) is in excess of 100 F. Unfortunately, many alkyllead antiknock fluid compositions which contain tetraethyllead and a scavenger combination of ethylene dibromide and ethylene dichloride wherein the molar quantity of the dichloride scavenger predominates over the dibromide, do not have flash points by Tag closed tester above 100 F. Varying factors contribute to the existence of this shortcoming. In the first place the ethylene dichloride scavenger 'which predominates over the ethylene dibromide in these tetraethyllead antiknock fluids has a flash point by Tag closed tester of about 56 F. Thus the presence of substantial amounts of this ingredient in the antiknock fluid contributes significantly to the problem at hand. Nonetheless, as explained in US. Pat. 2,398,281 it is very desirable to employ in alkyllead antiknock fluids, combinations of ethylene dibromide and ethylene dichloride with the molar amount of chlorine predominating, as this combination of scavengers efliciently and economically overcomes certain engine deposit problem s.

Another contributing factor to this problem is the presence in commercial antiknock fluids of this character of traces of low boiling impurities such as butane and ethyl chloride. These trace impurities tend to reduce the closed cup flash points to a significant extent. While it is possible to remove these trace impurities, their removal requires tedious and costly operations.

Thus there is a need in the art for an economical and 3,578,606 Patented May 11, 1971 eflicient way by which the closed cup flash points of the foregoing antiknock fluids may be raised to above F. without at the same time impairing other critical properties of the antiknock fluid compositions. The present invention fulfills this need.

In accordance with this invention, an alkyllead antiknock fluid composition containingtetraethyllead and an ethylene dibromide-ethylene dichloride scavenger combination in which the amount of the dichloride predominates over the dibromide, and normally having a flash point by Tag closed tester between about 50 and 100 F. is improved by additionally containing a small amount of methyl bromide, or ethyl bromide, or a mixture of the two. The amount of such material incorporated into the fluid composition is generally below about 1.5 percent based on the weight of the fluid composition and in all cases is suflicieut to raise the foregoing flash point to above 100 F.

As noted above, the compositions of this invention contain tetraethyllead as one of the essential ingredients. In one preferred embodiment, tetraethyllead is the sole tetraalkyllead component present therein. However, the invention is also applicable to various mixtures of methyl and ethyl lead alkyls, especially those which consist essentially of tetraethyllead, triethylmethyllead, and one or more of the compounds, diethyldimethyllead, ethyltrimethyllead, and tetramethyllead. Many such mixtures may be produced, for example, by the chemical redistribution between tetraethyllead and tetramethyllead. Generally speaking the problem of increasing the closed cup flash point is most serious when these redistributed alkyllead mixtures contain below about 40 percent methyl radicals with the balance being ethyl. Redistributed mixtures in which the methyl group predominates over the ethyl group tend to have, when admixed with the above scavenger combination, closed cup flash points greater than 100 F. even in the absence of methyl bromide or ethyl bromide or both. In any event, this invention is applicable to any tetraethyllead-containing antiknock fluid containing the foregoing scavenger combination where the flash point by Tag closed tester (ASTM designation: D 56-64) is normally between about 5 0 and 100 F.

Another prerequisite of the present compositions is that they contain an ethylene dibromide-ethylene dichloride scavenger combination in which the quantity of the dichloride predominates over the quantity of the dibromide. A wide variety of suitable scavenger combinations of this type are well known to the art and are described for example in US. 2,398,281, the full disclosure of which is incorporated in the present specification as if fully set forth herein. The present invention is particularly useful for improving the closed cup flash points of tetraethyllead-containing antiknock fluids in which the scavenger combination falls within the quadrilateral A, B, C, D of the figure in US. 2,398,281. From the commercial standpoint, systems containing about one-half theory of ethylene dibromide and about one theory of ethylene dichloride are most advantageous and are fully susceptible to the improvements provided pursuant to this invention. Accordingly, the presence in the compositions of this invention of these two halohydrocarbon scavengers in these particular proportions is especially preferred. However as noted the invention extends to other proportions of ethylene dibromide and ethylene dichloride provided that the amount of the dichloride predominates over the amount of the dibromide and the overall fluid composition has, in the absence of methyl bromide, ethyl bromide, or both, a closed cup flash point between about 50 and 100 F.

It is to be noted that even though the compositions of this invention contain a substantial quantity of ethylene dichloride (closed cup flash point: ca. 56 F.) the closed cup flash point of the resultant compositions is efliciently and economically raised to above 100 F.

The additives which bring about the foregoing advantageous elevation in closed cup flash point are used in very small quantities, normally below about 1.5 percent based on the Weight of the fluid composition. Of these additives, methyl bromide is distinctly preferred inasmuch as a much smaller amount thereof is required to achieve the necessary closed cup flash point elevation as compared to the required amount of ethyl bromide. For most antiknock fluid compositions of this invention the amount of methyl bromide will preferably range from about 0.1 to about 0.5 percent based on the Weight of the fluid composition. When employing ethyl bromide the amount thereof will preferably range from about 0.5 to about 1.0 percent based on the weight of the fluid composition. While greater amounts of these additives may be employed there is normally no advantage in doing so. In some cases even smaller amounts may be suflicient. If desired, combinations of methyl bromide and ethyl bromide may be employed and the minimum quantity will generally be in the order of about 0.3 percent based on the weight of the fluid composition.

Besides contributing materially to the safety in handling, transporting and storing the antiknock fluid compositions, the present invention is characterized by other advan tageous characteristics. For one thing, the amount of the methyl bromide or ethyl bromide or combination thereof is sufliciently small so that the other critical properties of the antiknock fluid composition are not significantly affected or impaired. Those skilled in the art are well aware that an ingredient in a commercial alkyllead antiknock fluid composition must not adversely affect its storage stability, its freezing point characteristics, its antiknock properties, or its engine durability characteristics. Neither methyl bromide nor ethyl bromide when employed in accordance with this invention causes any such difliculties. Moreover, the antiknock fluid compositions of this invention in all cases have open cup flash points (ASTM designation: D 1310-67) well in excess of 110 F., oftentimes in the order of about 200 F. or higher.

Another advantage is that all of the foregoing technical benefits are achieved at very low cost using readily available ingredients.

In order to illustrate the practice and advantages of this invention, the following examples are presented. It is to be understood that these examples are not to be construed as unduly limiting the scope of this invention.

EXAMPLE I To a sample of a commercial alkyllead antiknock fluid composed of tetraethyllead, about 0.5 theory of ethylene dibromide, about 1.0 theory of ethylene dichloride, and a very small quantity of kerosene and dye was added methyl bromide (0.13 gram/ 100 grams of the antiknock fluid). The resultant composition was subjected to ASTM method D 56-64 and found to have a closed cup flash point in excess of 104 F. In the absence of the methyl bromide this same antiknock fluid composition had a closed cup flash point of 62 F.

EXAMPLE II The procedure of Example I was repeated except that the concentration of the methyl bromide was 0.10 gram/ 100 grams of the antiknock fluid. Once again, the closed cup flash point was found to be in excess of 104 F.

EXAMPLE III The procedure of Example I was repeated several times using different quantities of ethyl bromide. It was found that amounts thereof of 2.8, 1.0, and 0.5 grams/ 100 grams of the alkyllead antiknock fluid resulted in each instance in a closed cup flash point greater than 104 F. However when the amount of ethyl bromide was reduced to 0.25

4 gram/ grams of the fluid the closed cup flash point was only 70 F. It will thus be seen (cf. Example II) that on a weight basis methyl bromide was considerably more effective than ethyl bromide.

The principal components of other typical antiknock fluids to which this invention is applicable are illustrated by the following:

(a) Tetraethyllead, 0.6 theory ethylene dibromide, 1.0 theory ethylene dichloride. The closed cup flash point of this fluid is easily raised from about 78 F. to above 100 F. by means of methyl bromide or ethyl bromide, or both.

(b) A redistributed mixture of tetramethyllead and tetraethyllead (10 percent of the alkyl radicals being methyl), 0.5 theory of ethylene dibromide and 1.0 theory of ethylene dichloride. The theoretical mole percentages of the ingredients of this redistributed mixture are as follows:

Percent Tetraethyllead 65.61 Triethylmethyllead 29.16 Diethyldimethyllead 4.86 Ethyltrimethyllead 0.36 Tetramethyllead 0.01

of the ingredients of this redistributed mixture are as follows:

Percent Tetraethyllead 31.64 Triethylmethyllead 42.19 Diethyldimethyllead 21.09 Ethyltrimethyllead 4.69 Tetramethyllead 0.39

The closed cup flash point of this fluid as produced commercially is normally in the range of about 58 F. and is readily raised to above 100 F. by means of methyl bromide or ethyl bromide, or both.

The antiknock fluids of this invention may contain small amounts of such typical ingredients as kerosene or other hydrocarbon blending aids, organic dyes for identiiication purposes, phosphorus-containing ignition control compounds (e.g., cresyl diphenyl phosphate, tricresyl phosphate, phenyldimethyl phosphate, etc.), supplemental antiknock agents (e.g., ferrocene, methyl ferrocene, methyl cyclopentadienyl manganese tricarbonyl, etc.), phenolic antioxidants (e.g., 2,6-di-tert-butyl phenol, 2,4,6-tri-tertbutyl phenol, 4-methyl-2,6-di-tert butyl phenol, etc.) corrosion inhibitors, toluene, and the like.

We claim:

1. In an alkyllead antiknock fluid composition containing tetraethyllead and an ethylene dibromide-ethylene dichloride scavenger combination in which the amount of the dichloride predominates over the dibrornide, and normally having a flash point between about 50 and 100 F., the improvement whereby said fluid composition additionally contains a small amount of a compound selected from the group consisting of methyl bromide, ethyl bromide, and mixtures thereof suflicient to raise said flash point to above 100 F., said compound being present in an amount of below about 1.5 percent based on the weight of the fluid composition.

2. The composition of claim 1 wherein tetraethyllead is the sole tetraalkyllead component present in the fluid composition.

3. The composition of claim 1 wherein said combination is about one-half theory of ethylene dibromide and about one theory of ethylene dichloride.

4. The composition of claim 1 wherein said compound is methyl bromide.

5. The composition of claim 1 wherein tetraethyllead is the sole tetraalkyllead component present in the fluid composition and wherein said compound is methyl bromide.

6. The composition of claim 1 wherein tetraethyllead is the sole tetraalkyllead component present in the fluid composition, wherein said compound is methyl bromide, and wherein said amount is from about 0.1 to about 0.5 percent based on the weight of the fluids composition.

7. The composition of claim 1 wherein tetraethyllead is the sole tetraalkyllead component present in the fluid composition, wherein said combination is about one-half theory of ethylene dibromide and about one theory of ethylene dichloride, wherein said compound is methyl bromide, and wherein said amount is from about 0.1 to about 0.5 percent based on the weight of the fluid composition.

8. The composition of claim 1 wherein said compound is ethyl bromide.

9. The composition of claim 1 wherein tetraethyllead is the sole tetraalkyllead component present in the fluid composition and wherein said compound is ethyl bromide.

10. The composition of claim 1 wherein tetraethyllead is the sole tetraalkyllead component present in the fluid composition, wherein said compound is ethyl bromide, and wherein said amount is from about 0.5 to about 1.0 percent based on the Weight of the fluid composition.

11. The composition of claim 1 wherein tetraethyllead is the sole tetraalkyllead component present in the fluid composition, wherein said combination is about one-half theory of ethylene dibromide and about one theory of ethylene dichloride, wherein said compound is ethyl bromide, and wherein said amount is from about 0.5 to about 1.0 percent based on the weight of the fluid composition.

12. The composition of claim 1 wherein the alkyllead components of said fluid composition consist essentially of tetraethyllead, triethylmethyllead, diethyldimethyllead, ethyltrimethyllead, and tetramethyllead.

13. The composition of claim 1 wherein the alkyllead components of said fluid composition consist essentially of tetraethyllead, triethylmethyllead, diethyldimethyllead, ethyltrimethyllead and tetramethyllead and wherein said combination is about one-half theory of ethylene dibromide and about one theory of ethylene dichloride.

14. The composition of claim 1 wherein the alkyllead components of said fluid composition consist essentially of tetraethyllead, triethylmethyllead, and one or more of the compounds diethyldimethyllead, ethyltrimethyllead, and tetramethyllead, wherein said combination is about one-half theory of ethylene dibromide and about one theory of ethylene dichloride, and wherein said amount is below about 1.5 percent based on the weight of the fluid composition.

References Cited UNITED STATES PATENTS 2,398,281 4/1946 Bartholomew 44-69 2,447,926 8/ 1948 Wiczer 252-386X 2,999,739 9/1961 Heron 4469 3,147,294 9/1964 Cook 252-386X FOREIGN PATENTS 1,078,259 8/1967 Great Britain 252-4386 1,092,337 11/1967 Great Britain 252386 DANIEL E. WYMAN, Primary Examiner W. I. SHINE, Assistant Examiner US. Cl. X.R. 44-69 

